The present invention relates to disposable absorbent articles. Disposable absorbent articles are considered to be absorbent devices designed to be worn externally of the body by a user and to receive fluids discharged from the body. In particular the present invention relates to disposable absorbent sanitary napkins, catamenials, incontinence inserts, and pantiliners that are adapted to form a three dimensional shape before use, in order to provide an enhanced fit for the body and reduced leakage by means of said tridimensional shape that matches the non-planar surfaces and the non-linear grooves of the body. The disposable absorbent articles of the present invention are preferably applied directly to the user""s body, and comprise improved side features which extend laterally and are capable of staying in close contact with the user""s inner thigh area, and adjacent to that, when the disposable absorbent article is applied to the user""s body.
In their basic form, disposable absorbent articles comprise an absorbent core interposed between a pervious body-contacting element (alternatively referred to as a topsheet or an overwrap) and an impervious protective barrier (alternatively referred to as a backsheet). The absorbent element is, of course, intended to receive and contain the fluids discharged from the body. The body-contacting element is intended to provide comfortable and dry-feeling contact with body surfaces while allowing free passage of fluids therethrough into the absorbent element. The protective barrier is intended to prevent the fluids which are expelled or which escape from the absorbent element from soiling the user""s garments.
Major disadvantages of known disposable absorbent articles intended to be worn externally of the body, e.g. leakage, wet/dirty feeling, discomfort, are related to the poor body fit achieved by these articles. With respect to e.g. sanitary napkins, different attempts have been made in order to provide such articles with the capability of conforming to the body anatomy. Body conforming absorbent articles are well known in the art, both those that are initially flat, and that are adapted to form a three dimensional shape before the use in order to match the wearer""s anatomy, for example by incorporating lines of preferential folding, and those that are already shaped prior to use in the desired three dimensional shape.
In European patent application No. 97122739.2 filed on Dec. 23, 1997, entitled xe2x80x9cTridimensional disposable absorbent article having a slit in the rear regionxe2x80x9d (PandG case CM1667Q), a tridimensional disposable absorbent article is described which has a tridimensional shape prior to use and comprises an upwardly convex rear region preferably having an inverted V shaped longitudinal ridge. The absorbent article also comprises a slit or cut in the rear region which extends from the rear end edge and is oriented substantially longitudinally. The rear cut or slit gives the preferably inverted V shaped rear portion of the absorbent article the capability of bending around an axis which is perpendicular to the symmetry plane of the article, in order to better fit the various body shapes, specifically in the area of the gluteal groove, where the rear region of the absorbent article preferably extends in order to provide a better protection. Preferably the tridimensional disposable absorbent article can be applied directly to the user""s body, rather than being applied first to the panty prior to wearing the panty itself with the attached absorbent article.
The tridimensional disposable absorbent article described in EP application No. 97122739.2 has the capability of better adjusting its shape, particularly its upwardly convex rear region, to the different anatomies taking into account the possible interactions with the undergarment, and any variations experienced during the wearing time, due e.g. to the wearer""s movements, at the same time providing a better fit and a proper positioning of the rear region interested by the rear slit or cut with respect to the preferred acquisition region of the absorbent article.
Disposable absorbent articles adapted to form a three dimensional shape before the use, particularly those being already shaped prior to use such as those described in the above mentioned application, do provide a good fit to the anatomy, and therefore a better comfort to the user and a reduced leakage.
This preferred type of articles, particularly the tridimensional disposable absorbent articles described in EP 97110735.4, can be advantageously applied directly to the user""s body, rather than being applied first to the panty prior to wearing the panty itself with the absorbent article attached thereon. This facilitates a good fit with the body anatomy, owing both to the preferred body conforming shape that the article can achieve, and also to the fact that a direct application to the body renders the body fitting capability of the absorbent article substantially independent of the different wearing habits and panty styles.
Side wrapping elements, or more simply side flaps or wings are a well known feature of disposable absorbent articles. Generally when absorbent articles, e.g. sanitary napkins, are provided with flaps, the flaps extend laterally from a central absorbent means and are intended to be folded around the edges of the wearer""s panties in the crotch region. Commonly, the flaps are provided with an attachment means for either affixing the flaps to the underside of the wearer""s panties or to the opposing flap. The flaps are particularly effective for preventing exudates from soiling the edges of the wearer""s panties, owing for example to side leakage of the article in case of mispositioning, or of particularly heavy flow. Flaps also prevent portions of the panty, particularly the panty elastics in the crotch region of the undergarment, from getting at least partially between the absorbent article and the user""s body, where they can contact fluid already present on the body facing surface of the absorbent article, or directly flowing from the body, therefore again leading to soiling of the undergarment.
Incorporation of side flaps in the body conforming absorbent articles mentioned above would be particularly desirable in order to increase protection of the wearer""s panties against soiling in these articles which are capable of staying very close to the body due to their good fit, but problems are encountered when this preferred type of articles is intended to be applied directly to the body, before the panties are worn.
According to the usual practice with known products, the absorbent article, e.g. a sanitary napkin, is first applied to the crotch area of the panty, e.g. by means of panty fastening means such as an adhesive means, and then the flaps are caused to wrap the edges of the panty in the crotch portion, and are typically folded, and preferably also attached, to the underside of the crotch portion of the panty. Absorbent articles comprising flaps that automatically wrap the sides of a wearer""s panties when the panties are pulled up, after the application of the absorbent article to the panties, are also disclosed for example in U.S. Pat. No. 5,558,663 and in U.S. Pat. No. 5,584,829. In both cases the flaps are caused to wrap the panties crotch once the article has been already applied to the panties.
In an absorbent article that is applied directly to the user""s body before the panties are pulled up a correct positioning of the flaps cannot be done straightforwardly. Once the absorbent article alone is applied to the wearer""s body the flaps have in fact to be kept by the user outside of the side edges of the panties in the crotch region while the panties are pulled up, in order to correctly cover said side edges and provide the desired protection against soiling. This requires attention by the user, and additional actions other than applying the article and subsequently wearing the panties, otherwise the flaps could be crumpled by the edges of the crotch area of the panties, which are also typically provided with elastic means. When the panties are pulled up and the edges move upwards along the inner part of the user""s thighs, the flaps can e.g. be folded irregularly at least partially between the garment facing surface of the absorbent article and the panties themselves, therefore providing a less effective wrapping action of the panties edges and a reduced protection against soiling. In some cases the flaps cannot even prevent the side edges of the panties from getting between the absorbent article and the user""s body, owing for example to a complete folding of the flaps against the garment facing surface of the absorbent article.
It is therefore an object of the present invention to provide a disposable absorbent article adapted to form a three dimensional shape before use, which is also intended to be applied directly to the user""s body before an undergarment is worn, having side features capable of effectively staying over the edges of the panties in the crotch area, and of covering them to provide protection against side leakage and soiling.
It is a further object of the present invention to provide such a disposable absorbent article in which said side features are comprised in side flaps, in order to keep said side flaps in close contact, and adjacent to, the respective user""s inner thigh area during panty pull up.
The present invention refers to a disposable absorbent article adapted to form a three dimensional shape before use, comprising a main body portion, a liquid pervious topsheet, a backsheet joined to said topsheet, an absorbent core intermediate the topsheet and the backsheet, a body facing surface, a garment facing surface, a longitudinal symmetry plane, and a pair of longitudinal side edges; the absorbent core has a front portion, a central portion and a rear portion, respectively corresponding to a front section, a central section, and a rear section of the main body portion,
wherein at each of the longitudinal side edges at least one rider element is joined to the main body portion, wherein each of the rider elements has a bending stiffness of at least 0.02 N as defined in the Bending Stiffness Test described herein.